There are many medical symptoms and physical conditions which, in one way or another, limit the mobility of the ailing person. For these persons (referred to herein as subjects or users) affected with medical symptoms which prevent them from balancing, standing, walking, gait, or locomoting in a normal and/or ideal fashion, it may be difficult to teach these people to correctly walk while applying a limited amount of weight to the lower extremities, such as the person's foot or feet. It is commonplace for healthcare professionals to advise or instruct users not to exceed a certain weight limit or load on their feet, commonly referred to as limited weight bearing, to prevent injury or facilitate healing. In particular, the user may be advised by a healthcare professional to perform certain exercises, while maintaining the reduced weight pressure on the user's foot. Sometimes, healthcare professionals may prescribe the use of crutches or a cam boot to a patient, which may be accompanied by instruction to reduce the pressure exerted on the foot while in use.
However, many subjects have difficulty performing exercises as instructed by health care professionals. Users performing such exercises typically exert too much weight on the foot, which can cause further damage or slow the healing process. Thus, a device that monitors and provides feedback as to the pressure level exerted on the foot is useful to those in need, so that the user can be aware of when they have exceeded the recommended pressure level, and can reduce the pressure. There are currently several in-shoe monitoring devices that monitor pressure distributions during walking using thin film inserts; however, devices currently marketed have not been widely adopted clinically because of their relatively high cost, especially for those devices incorporating electrical components, and many fail to provide a suitable tactile feedback to the user. In addition, many devices include several components, such as components placed proximal to the foot as well as components clipped onto the user's body. Other devices incorporate wires or other electrical signal-generating aspects, batteries, transmitters, and other complex equipment. These devices are not only cumbersome and expensive, but are additionally prone to malfunction.
One type of weight bearing indicator has been developed as a low cost alternative, which includes a free-standing mechanical snap-dome device placed within footgear, providing both audible and tactile biofeedback to the subject, such as that summarized in U.S. Pat. No. 6,405,606. However, such snap-dome devices suffer from severe limitations. One particular limitation is that if force is not applied directly through the center of the device (directly downward), the dome may not properly snap, and thus will not register or provide feedback regarding the applied force. In fact, this limitation occurs fairly often, since the distribution of the force on the bottom of the foot changes as the user progresses from heel-strike to toe-off during normal ambulation. As a result, users that perform instructed or advised exercises with these snap-dome devices often apply excessive weight loads at an angle in the foot bed which does not pass through a traditional snap dome loading device. The snap-dome device does not provide audible or tactile feedback, which may deceive the user into thinking that they are complying with medical advice while the unmeasured excessive loads may, in fact, injure or prolong the recovery of the user. Further, the tactile or acoustic alarms of a free-standing snap-dome device may slip out of place or otherwise move during typical locomotion.
Based on the shortcomings of the devices currently used today, there exists a need for a full-sole weight bearing apparatus which will allow the user to monitor the pressure applied to the foot safely and securely, and which overcomes the problems associated with such weight bearing apparatuses currently marketed.